Hi , i have a Micra K12 2003 that was fine until the battery went faulty and had to be replaced. The car has the intelligent keys and the key fob opens and locks the car but the engine will not crank or start with the red key symbol lit all the time the ignition is on

I think the ecu has lost the key programming as nothing else has changed. The details from the glove box says K121151201 97BBD52ED136 23095586 , I Called Nissan and was told they use rolling codes and are online only so no help . I have a Autel Maxisys diagnostic computer that will program keys but asks for a 5 digit pin code . it also gives a 4 digit pass code but that did not work, The only code i could find was 2DE2056734A but did not work and is not 4 or five digits.

The module under the ignition switch is Nissan Calsonic kansei corp Model no BSREU19 part No 2850 C9966 serial 0053979. i have checked all fuses and read fault codes but the engine ecu has P1611 NATS as the fault code and will not erase .

Thanks in advance for your help and hope you can help me solve this problem